3-Hydroxyaldehydes are useful chemical intermediates. They can be readily converted to 1,3-diols which are useful as a chemical intermediates in the formation of polyethers, polyesters, polyoxyalkalene glycols which find use in fibers, additives, stabilizers and the like.
U.S. Pat. No. 3,463,819 and No. 3,456,017 teach a process for the hydroformylation of epoxides to produce 1,3-diols and 3-hydroxyaldehydes using phosphine-modified cobalt carbonyl catalysts. While these references teach the production of both 1,3-diols and 3-hydroxyaldehydes, only a small amount of the 3-hydroxyaldehydes are produced. These references use a large amount of catalyst compared to the starting epoxide amounts used and this large amount of catalyst used hydrogenates the aldehyde to the diol. The use of large amounts of catalyst is expensive and can make a commercial process uneconomical. The hydroformylation of epoxides of higher carbon number than ethylene oxide produces lower selectivities and yields of product when compared to the hydroformylation of ethylene oxide.
U.S. Pat. No. 3,687,981 uses cobalt octacarbonyl as a catalyst and discloses hydroquinone as a catalyst stabilizer in the hydroformylation of ethylene oxide. Inorganic halogen-containing compounds, such as hydrochloric acid, are disclosed hydroformylation promoters, i.e., compounds that increase the conversion of ethylene oxide to the desired product. Trace amounts are said to be useful.
In U.S. Pat. No. 3,401,204 and No. 3,527,818 ditertiary phosphine ligands and cobalt catalysts prepared therefrom are described as being suitable for hydroformylating olefins to alcohols.
It is an object of this invention to use an improved cobalt-ditertiary phosphine ligand catalyst to hydroformylate epoxides having carbon numbers greater than two to the corresponding 3-hydroxyaldehyde product in high selectivity, which 3-hydroxyaldehydes can, if desired, then be hydrogenated with hydrogen to 1,3-diols in substantially quantitative yield using conventional hydrogenation catalysts.
It is a preferred object of this invention to operate the hydroformylation reaction with minimum amounts of catalysts under conditions to produce as the primary product 3-hydroxyaldehyde which may be used as such or as a chemical intermediate or which may subsequently hydrogenated with hydrogen to a 1,3-diol.